[SOLVED] How to get the number of files in a folder as a variable?

Issue

Using bash, how can one get the number of files in a folder, excluding directories from a shell script without the interpreter complaining?

With the help of a friend, I've tried

$files=$(find ../ -maxdepth 1 -type f | sort -n)
$num=$("ls -l" | "grep ^-" | "wc -l")

which returns from the command line:

../1-prefix_blended_fused.jpg: No such file or directory
ls -l :  command not found
grep ^-: command not found
wc -l:   command not found

respectively. These commands work on the command line, but NOT with a bash script.

Given a file filled with image files formatted like 1-pano.jpg, I want to grab all the images in the directory to get the largest numbered file to tack onto the next image being processed.

Why the discrepancy?

Solution

The quotes are causing the error messages.

To get a count of files in the directory:

shopt -s nullglob
numfiles=(*)
numfiles=${#numfiles[@]}

which creates an array and then replaces it with the count of its elements. This will include files and directories, but not dotfiles or . or .. or other dotted directories.

Use nullglob so an empty directory gives a count of 0 instead of 1.

You can instead use find -type f or you can count the directories and subtract:

# continuing from above
numdirs=(*/)
numdirs=${#numdirs[@]}
(( numfiles -= numdirs ))

Also see "How can I find the latest (newest, earliest, oldest) file in a directory?"

You can have as many spaces as you want inside an execution block. They often aid in readability. The only downside is that they make the file a little larger and may slow initial parsing (only) slightly. There are a few places that must have spaces (e.g. around [, [[, ], ]] and = in comparisons) and a few that must not (e.g. around = in an assignment.

Answered By - Dennis Williamson

Answer Checked By - Timothy Miller (WPSolving Admin)